A preliminary study on edible, antimicrobial extruded films made from pectin and other food hydrocolloids

Authors: Liu, Linshu; Jin, Zhonglin; Liu, Cheng Kung; Hicks, Kevin; MOHANTY, AMAR - UNIV. OF MICHIGAN STATE; BHARDWAJ, RAHUL - UNIV. OF MICHIGAN STATE; MISRA, MANJUSRI - UNIV. OF MICHIGAN STATE

Submitted to: Journal of Natural Fibers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2007
Publication Date: 8/4/2008
Citation: Liu, L.S., Jin, Z.T., Liu, C., Hicks, K.B., Mohanty, A.K., Bhardwaj, R., Misra, M. 2008. A preliminary study on edible, antimicrobial extruded films made from pectin and other food hydrocolloids. Journal of Natural Fibers. 5(4):366-382.

Interpretive Summary: Millions of pounds of potentially valuable pectin are present in the low-valued pulp and peel generated yearly by the U.S. beet sugar and fruit juice industries. However, only a negligible amount of pectin is extracted and marketed in the U.S., due to it's limited commercial markets. Finding new uses for this biodegradable polysaccharide is critical for the long term economic viability of U.S sugar beet and citrus agribusinesses. In this study, we made pectin composite films by extrusion with other edible hydrocolloids, such as poly(ethylene oxide). We also incorporated a food-grade antimicrobial compound into the film during extrusion and then used those films to package food products. The new composite films have a wide range of textural characteristics that can be used to alter the mouth feel of packed foods. The composite films resist spoilage and the growth of a dangerous food pathogen, Listeria monocytogenes, because of the presence of the food-grade antimicrobial compound. Thus, the composite films can function as novel antimicrobial food packaging/coating materials. The research and development of such materials will help to develop new markets for pectin and eventually create new uses and value for sugar beet and citrus byproducts.

Technical Abstract: Antimicrobial edible films were prepared from the natural fibers, pectin and other food hydrocolloids e. g., poly(ethylene oxide), for food packaging or wrapping by extrusion followed by the compression or the blown film method. Microscopic analysis revealed extruded pellets with well-mixed integrated structures made of evenly distributed synthetic hydrocolloids in the biopolymers. The resultant composite films possess the mechanical properties that are comparable to films cast from most natural hydrocolloids that are consumed as foods or ingredients in processed foods. The inclusion of poly(ethylene oxide) alters the texture of the resultant composite film and therefore, demonstrates a new technique for the modification of film properties. The composite films were produced during mild processing conditions, thus, the films protect the bioactivity of an incorporated bacteriocin, nisin, as shown by the inhibition of Listeria monocytogenes bacterial growth.